A514 is a particular type of high strength steel, which is quenched and tempered alloy steel, with a yield strength of 100,000 psi (100 ksi or approximately 700 MPa).
A517 is a closely related alloy that is used for the production of high-strength pressure vessels.
[1][2] A517 steel has equal tensile yield strength, but slightly higher specified ultimate strength of 115–135 ksi (793–931 MPa) for thicknesses up to 2.5 inches (63.5 mm) and 105–135 ksi (724–931 MPa) for thicknesses 2.5 to 6.0 inches (63.5 to 152.4 mm).
It is normally used as a structural steel in building construction, cranes, or other large machines supporting high loads.
In addition, A514 steels are specified by military standards (ETL 18-11) for use as small-arms firing range baffles and deflector plates.